SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7bdc05b47d34bb59612be05ce853c5462ee681edd738abeb8af1c16821387f5' 
  AND token = 'CqFS9y9Xw9i3+Du46Ozw+PH25Z2hogNbMAdrb8RfeTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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