SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42d20e0fc187d3f9369999c7797ab81db3977b1655acc38125c56221210aaa10' 
  AND token = 'naWOEgfgUYhAMg+yzbo2APl676r/zr8yGBXRgvywAwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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