SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'aee893e7c12a2838147a7fd631d3bcdd0b07adf37058dab083e21a3d1b59d1bc' 
  AND token = 'SQOs7h/fN1LXrmf1fX55Lkt6cQp9V6NktBdUYpVpgbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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