SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35627ac0385f33939c19e1f201f55c788e13649cb5bc365ebe34ba75549b370c' 
  AND token = 'l0cUSEBtvdzG3VhfOJ9dF/DxJpx1jeE3QYK711hcv88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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