SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5035409406d29b40d8954cad0eda374874fe01c8ec1190f8df9640661eb99150' 
  AND token = 'Cnxj0Kgh1+ReafcqZQzXMTf4X4bWPY5y/0W/luYrD4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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