SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0b5688a97b7e6647a4d567cbc06989db944c8c4e3f64fadd014037fbadb0ef' 
  AND token = 'yIeAtOg0DXXrMlzDBOp5VwlnbfPW1mJoI1xzhS9QgP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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