SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f04483a32748706c3e8fb5344d28f46a7eed7d6af5b751bb788ed3ee145d640' 
  AND token = '+T2lVBprZTi7gtGhfZbMyegeqSsVCpf3YmH11sFgsRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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