SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c4ce70e2740fd3c21757aace296e411befc947a826f163ad55a4a8fa5a2f2f' 
  AND token = 'c0rzAY1I2PBtTzPN9IHiCY2y8j2etKIAZAEhKD4MxTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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