SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50488c4397ef61113f40a3544447260c6ee12c86eabc9ced7b1602bfd4469fb9' 
  AND token = 'X9wTMJJop1jScw5CUGzgL7zKTaCC+q/3HdKS6VI/4Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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