SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b6706a59832f8dfcf89b7f1a5062f35464edc9ad2884555cf38be6fd312eccd' 
  AND token = '3sXuQT/9LDjyP4/7uDyD4YctW0T/LEDSMJLnkRyebag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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