SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeee36a47c74e243d66303d50f31793e30c5f3d0edd8180d9b1720f839fb6656' 
  AND token = 'QptMAd0D1FteUysManKmkv56/HucTB0lxtb+UmreY/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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