SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '56304d7f0bf5d6289952c15aef0eb05a2fb865adc1ea09026a6d0de8a99a4703' 
  AND token = 'gsGwu0kvvY8RRPds0qOW8jOmAg1naR8i5PnjQVnV/98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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