SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f720ba6d36c6296ab2ea9e688a653387e320014e8dcfd45c1960f61e7f85b77' 
  AND token = 'yRwMC97qy7LYVI6EpZOzz+/9cR2CJfuW1mip55GxSB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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