SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f6c0263878e4919986cdd1d0109993c1fb5f7ee11aca5cd6c30a152d935f33a' 
  AND token = 'UOv3TS1MpUv/UbIySSs6QIVBiPWRqTEfPGJFAJQGPSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}