SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '538b8360ededaf3d758b63d806d042f987acabcc6c0ea3bd81579e47288530dd' 
  AND token = 'qkxMVgjjVunbCE2JL1dw3bHRmiomCkJaija0A/ZiF60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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