SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0437e925f4845ff5a62ba2900dd974e4ff83a7038316757cf8f055a15f045a3c' 
  AND token = '6DX7EIMQ6aUDpO9bAiPl5X6CyJY7PGwzu+WEdCQWifE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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