SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c79c248ee0a05ec51b5fd040c5c785e325c11f6249a36b17af0b11b6611f6b42' 
  AND token = 'KJRaPh4yTA0DrL5QPj3M1m800ZQgPK1Wyp43ucU0aoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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