SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cea3984b76ef0cbb0c19ae1ad85843a79ccc0253f3259d8d86a45298d75f96bd' 
  AND token = 'BjImXiOuGA0BxVDFNGtqeRrVLxAVk6v3pfISI1VMZWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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