SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a98f4992c660f9c936a13485c4c2ccfaef1eba2ab7dae2aa6f8fc93967f45e9' 
  AND token = 'BNWt1NvYZbrj0GohYf+RKVzxjXMu5vlDCqiDvdZYqLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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