SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5a75bf9f2479d65cfd8894985f88ae29653dee68690c9fb3d26b83f411baaaef' 
  AND token = 'UmAj0xtSayXIH6rL7eZ84RF17sMmQdrOg91mE4g2N6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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