SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '847280b9914953434a3fcbd2b8b3181d67a7ec2b52a5505bb37f0c6c26ae293f' 
  AND token = 'R8j2Ox1Wjz+D+ODjRZjyEdxBPYFMPKgMW09/wy7Zw1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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