SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74ef04c92e2343f06b63bcc473409ac97f064f01b3b15f350f094bf105ced260' 
  AND token = 'RT5n5xHH7N46aTNZRfjmlZXTw65G0W5yUVwNHmRXRqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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