SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5642523ffc78f89520189d4b4642f5fceb6772a88294ef42bffc5f3243f52a31' 
  AND token = 'vCwsAn/NfcVhzjaCp1tTi5sjdmnzxqE3oe/yJjG+RTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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