SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb99b3fb67b4577f8de7e413b99b48405e8d427314557c63ae4eeb3ef9a1ee3f' 
  AND token = 'ZSaJhfqiR+NnTnD20b72vhFhHCxjNVJCx/wq18Ru+K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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