SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53ee69d6c4d31cec64d4b7bbab2362a5f127f3d9d3514ccc9339f1299e7e9097' 
  AND token = 'yQTdVT8HnznWsKTd899AZ0/fR09zHpEoQ8cgtvJYiHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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