SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '876d990a85e3c5873c8a2fbb73a1a4fb7826d1f6440735fed5fd02f076a45382' 
  AND token = 'YX3+bQl44dtT/N8GCwVHbYlOwFCFtZhq5PyviO0b8S4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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