SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95510a7f62015845f951874917ae2fdc7275d1541f1177b89bda0aa4f89d8a6c' 
  AND token = 'vuhZgu2ATjBvJgXZe776UzrGEVQX2rA77Aj8FGoIwy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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