SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3676fc263696f0b64527688346c118ed685c14a07f5f6d07182789309d1dfc78' 
  AND token = 'JuXnKNakAXy8ROgHxOQ/ryvGp5hz9+SX4t98A3dkC38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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