SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76c0d6e27d482b3e966e8de62ca5857e0d4d46073c8bd369b011cf4502c64eb2' 
  AND token = 'EwPMLgz1L2d9v+IJz0lmSTXJ1LVI3J+1TYqGhvYK2Uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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