SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e66a8271aabb2f0503ac63f2b24c23e9f59762a300fe3edfa47e36ad2b906dff' 
  AND token = 'bRmGqGYT9IgvMRfBhT0dyKq8jwE98+KTBYdBxrZM8kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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