SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3782606a7229fbf3a8e33f016bd2520d2e902c2d56ad8d7b4f93c7cff5bc02' 
  AND token = 'cXex15HsJZsX/Ajx/g3Fi9Op56J1K0yXvCnEVGRncjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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