SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e004cfafd592ab6c4e71d0530b39e2f6459901415f311fff30ab1f6f1673c276' 
  AND token = 'QR+FQUL/Ce7cChb57TJrhoIB9a1rxB3Ih6ZbAIUrX5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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