SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd220e1f38665dad94fe56799666d478ef1d21f53ada9c3d71da01808a0fdb4f3' 
  AND token = 'CLLKSzBVDoyorNRGCZNtRC3iSGhwDox7oE3HvxRigcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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