SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fc35457118657deb03e74fda4da932c41fabffe7d36c809eb73117cc820d25' 
  AND token = 'MtEBkCDNLoTKGA9+/A3RZcxjiEqBxiYVnBKxAh5FMv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}