SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '344e5a2eaba4503fe8091cee89797340669b18823324e06bd7156287ad993713' 
  AND token = '0EghbZbdpf2EnP8BFVWilXL4gm6X/WkPoBUxSay0zVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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