SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '988d5937b28210f5aeec7662b95306aca3376cbad473f93a439b65186c78b0fd' 
  AND token = 'lm16OpY/yOReNICV4jL1Bh9QU2fVkRoesesd2xZF/gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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