SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ae971930fb3831ef372e40a95152f4ac1a0e30a60c87b098700d3b5f6586685' 
  AND token = 'UKSuJ2G9w/oxG5DwWk3+/kt/Fusg1r3eKJXB+hoZoL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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