SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fd0c991ba8cc88744fff47e108b866f396659147934bd16eee65c2e2571042e' 
  AND token = 'lZy5ZVBYnlmqQ9Cht0/UrNh7glFQwG1PRFrDv6loXE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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