SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '400e2b9843c6149bfdb1e99618e598ec96f36311aaaed3a477453c0a01b5aafa' 
  AND token = 'OiNIANhL2u8/+Gor3/RKdrgMt1OnL/dgzUUWwb2yGM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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