SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75d4fecd138e3bca5f428b025cdc3d3137fee84c6e760c0433a0925de30a4dd8' 
  AND token = 'zJriJJtE5IaGhLnrbCa4o0pXUrkk+m2Gw5vT+jjYj2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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