SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9510c12d82b1bf3ae7f77a60b2d03b62f72051de6accb7f09c0c975989aaff' 
  AND token = 'LNkn5w/+AkIh/UjvFT+ue6UDb1U4lse9ro5n4Kbvr/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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