SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d3b17590149d01ffc9901ad8c88cd93dbbeecf97219adcefd16ed814e7dd16d' 
  AND token = '30U2BWzb4jttrzobi8yjHs3L2aoU/eQ9SKeToXAjddI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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