SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a4e9cabdf6fcbd2ea481ac74bea63e90d81160dcb95880a9e02615a04a9101' 
  AND token = 'Lc0LOgSvgO2qHVrih++wCOrPlBWx1DAsL8e+iVI3ybA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}