SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b254ea18c43f6cbe1bd4b1fc67db8052e819ba9b1b066192c0c91dc3e6766de8' 
  AND token = '8dN/TtI3tIWQdllhXCMzyWteAf0NTyX1c8w5cloPn4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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