SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38c962de0637d2e525b8ca6a3d3a61563e47c09db3cc42ab2f0aeafa9cf950a0' 
  AND token = 'O/JJqXoJ8HVWgFdrUGBtoj+zU2nWCsfp3/5q/xlqlp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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